IMHO, what people call biological clock is only 30, 35, 40 years peer pressure coming down on you. Maybe you don't want children, but you keep hearing what a great experience it is, that there is nothing like it, blah, blah and stories like flower70's all over the place, so when you reach a certain age some women might get insecure, kind of: "what if regret it later? It is now or never!!!!". And I know for a fact that not all stories have a happy ending: Of course some do but those are the ones people love to talk about. Nobody talks about having children for the wrong reasons and regretting it.
